Apparatus for the specific gravity classification of bulk substances



INVENTOR. 71/6 Z fer Va eZ BY W. VOgEL. APPARATUS FOR ECIF'IC GRAVITY CLASSIFICATION" OF BULK SUBSTANCES F1164 July 23, 194'? Sept. 30, 1952 v ties.

Patented Sept 30, 1952 STATES TENT cr tical APPARATUS FOR v"ma SPECIFIC. GRAVITY;

CLASSIFICATION OF BULK} SUBSTANCES Walter Vdg'el, Santiag0, can;

ApplicationJtiiyZit, 1947,; Serial Noi 763,121

In Switzerland September 11- 1946 Claims; (c1. cos-422) v.I-heipresent invention relates to apparatus for the .7 specific gravity classification of bulk sub stances; .-utiliz,ing, finely granulated separating media. ,rsuchvseparating media may be sand, gravel or other materialreduced to suitable size,

ingrconjunction with apparatus H adequate for carryingthe process into effect.

1 More specifically the invention relates to apparatus for specific gravity classification of bulk substances in which the finely granulatedflmedia and thematerial to be separated new in strata in an inclined'stream greaterthan the natural angle of repose oi the media and including means for 1 discharging the mediaxafter first changingthe direction of flow thereof at different relative velocities.

German Patent.740,005 discloses a process ifor accomplishing separation in a stream of a finely granulated separating. medium advancing in an adequate trough: with the velocity of the diverse layers thereof increasing from the lower to the upper layers.v In such case the stream of sepa rating medium conducts itself as ii. it were a liquid in which,: in accordance with the Archimedean principle; the heavier particles gradually sink' to the bottom of the separating medium and the lighter particles are-carried to the-top. In this known process the diverse velocities of-"the the various sections where the diverse layers'of separating medium impinge upon same. '1

The specific'gravity classification of morethan two substances can very conver'iiently beaccomplished 'by means of this invention an'd'io'r this purpose two or more superimposed layers otsepa rating media diminishingin specific gravity from" the bottom to the top. are used simultaneously If forexample it is desired to obtain-three prod} ucts, two finely granulated separating media oi diverse specific gravity are used, that 'is,' an uppe'r layer ofilesser specific gravity over alo'werlayer of greater specific gravity, rThese'layer-s'advance in the trough simultaneously. At the discharge end of the trough the light weight substance will v be in the uppermost layer, the middle weightsubstance will be in the intermediate layer, and the heavy weight substance-will be in the lowermost advance-movement of the finely granulated separating-medium is achieved by expedient election of the, angleof the slope of the trough in the interior of whichthe separating process is accomplished; as well-as by adjustment of a blade for dividing;- the stream of separating medium, located at the discharge end 01 the trough. Experiments have-shown that in this manner it is not possible to accomplish satisfactory separation because of the fact that the diverse velocities, upon'which principle this separating process is based; do'not remain constant throughout the separat medium until it reaches the discharge -'1herefore-,' the? present invention has for an object the elimination of these difficulties and the provision of structure that permits adequate separation, the intensity oi. which can be reg'ur latedat will inasmuch as adequate provision has been" made I to insure discharge oflthe diverse layerspi-the separating medium at diverse veloci:

' separating media from'the trough over one or more movable surfaces placed at an adequate angle? in relation to the advance movement thereof, Th'e'-velocity oi, these surfaces difiers in process. 1

aforementioned.

It is advantageous to use separatingmedia-having similar angles of repose. -In;some-cases-,- in order toavoid intermingling of the layers it-may .be expedient that the granulations-of the separating medium of -greater, specific gravity;; ,be smaller than the granulationsotthe separating medium of lesser specific gravity; Itjmay also be advantageous to have between thetwo layers of separating media of diverse specific gravities, an intermediate layer composed of .aamixture of the adjoining layers which mixture. generally forms spontaneously during operation 5 of; awe-,- ratus covered by this invention. -v 58 1 r In order to maintain a constant separative intensity. the specificgravities as well as the angles of repose of the granulates of separating the 'inclusion of extraneous material m For greater convenience it i's q-ssibley-to' pass through a cleaning device, a partial stream of the separating medium used inany closed. circuit. The method used may be, for exk i plfl .v either whic'hdiminishes'the'puritythereoflas a esultoi hydrom'echanical separation adecantation machine, or pneumatic cleaning by meansio'fqair currents. If the hydrom'echan al mQlihQdLuiS used, the cleaned separat n mediumhmusinbe dried. before being re-used" in the separating Meet? advantages a e named separating medium a material capable of being magnetized, the cleaning of which may subsequently be accomplished by magnetic separation,

by merely; passing a'partial streamofthe s'epaw rating medium over an adequate magnetic field.

The purpose of this invention may also be;-

achieved by using as a separating medium,hollow has; a discharge/"opening iron balls, in sizes and Wall thicknesse propertionate to the specific gravity desired." wise possible to use cast materials, such as; metal lic alloys or glass, slag and ceramic materials,

such as porcelain or materials hel'd together -bymeans of resins or other binding agents, including ferrous aggregates, in any given size required,

and also, if necessary, spherical in structure. The

thererro'm by a-simple screening operation. For

this purpose the-size 0f granulation chosen rqr the separating medium must be larger than the size ='-'o"f the part oration or mesh of the screen used therefor. For example, inthe-separation of stock'piledbulk-coal, the separating, media useu' 'may he-hollow cast steel or basalt balls, or solidglas's balls8 to l-o'mmsl "in diameter. Thus a 12mm. mesh screen may be used toreeovr the substance to v be separated, and i an 8 m-m.-= mesh" -'screenmay be used to recover the separating medium; f-r'om= th'e "residue; and ifthe screenhe combinedwith a -conveyer, it-will be possible-to return in-ga"continuous-manner, the screened separating medium to the principalciredit of the process .effectedby this invention.

@The invention will now be described with-particular' reference t the accompanying drawings in which 'Figure-* 1- is' -a= verticahcross sectional View or 150118 iorm of'apparatus utilizing-a "re volvingplate' for discharging'-the"layers' or strata the trough to the aforementioned revolving plate.

Looking in the direction, of rotation of the revolving platet, the frontmwall la of trough I,

to s'aid revolving plate. As a result of the rotation of revolving plate 5, the separating medium leaves the trough laterally at a velocity which increases from the rim-of disk I to the perimeter of revolving plate"'5'. Above revolving plate 5 there are}, two stationary dividing blades 9 and 9a., which slope at an angle corresponding to the angle rofrepose of the substance to be separated.

Grie of thedividing blades 9, commences slightly beyond. the lateral discharge opening 8, of the r" trough,and separates the exterior layer SI, containing the light weight substanceirom layer S2, containing the heavyweight sub'stanceZ Exterior 1 layer 81,- is gradually advanced by fan'djialor ifg dividingblade 9,:to theperimeterofiirevolvirig plate 5, and-then drops into a collec'tion recep tajcle, not shown. :Interio'r layer S2.,-:=containing the heavy weight substance, rotates withrevolv ing plate 5, and islikewise gradually advanced by and along dividing blade' 9a,, to theiperim'eter of'revolving plate i'un'til itdrops off. Revolving plate 5 is driven lby-any conventional means-and rotates at such a. velocity that the. advance :movem'ent of the separating..-medium :theitroughfils I not obstructed. V

"Theimodified form of execution or the iapparae tus hereinbefore idescrlbed; of which Figure Eris I a vertical cross section and Figure 4 issaihorizontal cross section, .ldiffers from the-preceding formiof execution only in-thatfQntI'UHCQtQdflCOHQ shapeddisk H1, is mounted-above revolving plate 5,:notv concentrically but zra'thereccentrioallyzgin relation ;to the-supporting shaft 6; of *saidvrevolvingV-plate 5; .Thecdiameter. of-disk l0,-iis-such that-none side :of 'itsrsur afie pr je beyond the edge of revolving. plate-.5. Disk ;|;0.'-rests;-upon revolving plate 5 -and.-;may 'bel rotated eilther around {shaft ll onswhich shaft ll may beia propelling shaft, andconventional driving'means wh h ar "n thown. are u l zed. hi disk at difierent relative velocitie's, Figure'zisa horiatlonbf the "apparatus shown in'the accompa y."

ing drawings.

' v I Theformof apparatus "shown'jin Figures and 2 comprises"a downwardly sloping covered'trough I, at the head or upperend of Wh'lqhf'theije is a double' feed hopper including inlet funnels V {and 3;-=for receiving'the' separating media, an

substance .to-be separated is fe'd'." .The'fdlscharge endsof trough projects over the surface -ofa revolving plate 5, supportedoni shaft Comcentrically above --revolving plate 5; there isja trun'cated-cone-shaped disk' 7,"Whose jsujrfacev 1c, slopes along the sameplane as the bottom fifths trough, and said surface servesjtord rfi 't the' lower layer SII,- o'f' the separating media, 'from v be-,- tween said'funnels, a ductll, through which the may :-also;.be propelled by freVQIVingfidiSkfiE. Due t th re ri of: disk-UL: i s rves;sim 1tan ously to dividethe separating medium: and to ai t n he-d erse .s ayersc-th rcof L er @S and S21 are dropped one after the; othe r ;-from the im r of revo vi p1 e 5im'l ig wei ht products'Sj, will be the;first-,to drop ojfp and subsequently the heavy weight-products, $2., wi-ll r al y-d o Se ere iQnm i a e -rth products dropped from therevolvingplate,issacv compl-ished by means-of adjustable blades enoteddiagrammatically .at 12 r other similar devices accomplishing this result. Inasn uch- -as in this'case there are no dividing blades on, e-

vs n Pl -W i =h hes ear i es sm sl' advances, it is impossible for the. separating medium to choke before leaving'the-trough. is-hafts Band I l,..and hence-revolvingrplate iitand disk ,l0,.may alsobe" used in -;a'n in lined position.

lri ,Ibo'thforms of execution reinbefo're delst r be both the bot ri i sh an ith s de wall facing the direction of "rotation terminate approximately on the same plane asv; the upper I v i'ip riacen the surface of the .plate-I5"and. he top walli'p'f the trough likewiseextendsidowri-arid terminates in the same plane. as the opposite side walls. Thus, the mater nd edia nowns ddw. 11B nt r da r i s -on' r isthar eli-la ral the'troughdue to 'the rotation'of plate 5.

mitt-ls therefore clearuthat I haveaprovidedan apparatus including the covered trough l sloped at anangle slightly greater than the natural anglerofrepose of the masses of separating media, which as indicated previously are finely granulated material such as sand, gravel and the like. At the head or. upper end of the trough are plural feedv means communicating with the trough comprising funnels or hoppers 2 and 3 respectively receiving and discharging-into the trough finely granulated separating media of different specific gravities and a duct or pipe 4 into which is fed the material to be classified, such as bulk coal. The trough of course, due to its inclination and length, is such that in the dry stream flowing therethrough stratification will occur in such fashion that the light weight constituents of the masses will be at the top of the stream, the heavy weight constituents will be at the bottom and the intermediate layer or strata will comprise the substance of intermediate speciiicgravities. The bottom oi the trough extends down to and terminates approximately in the plane of the upper surface of the truncated cone-shaped disk I or III, as the case may be, the-Itop of the trough extends down and terminatesimmedlately above the revolving plate 5 beneath the disk I or 10. The side wall of the trough facing the direction of rotation is broken awayand'terminates with the lower edge substantially in the plane of the upper surface of the disk I or ID. Thus, the strata flowing down the trough at'an angle meet the revolving plate which is shown disposed horizontally and has its direction changed. The revolving plate continues. the advance or feed of the material from the trough and conveys it laterally away from the trough. Inasmuch as the velocity ofportions of the plate increase from its axis outward to its perimeter the different strata, particularly the lighter strata at the top of the trough and the heavy strata at the bottom, will impinge upon the plate at portions traveling at different relativevelocities. It is noted that the slope of the disks approximately the same angle as the slope in the bottom of the trough. Thus, the rotation of the plate will impart movement to thestrata such that the light weight material will tend to move radially and advance toward the perimeter of the plate. the stationary blades 9 and 9a, which as shown are inclined at approximately the same angle as the angle of the trough, divide'the stream so that the light weight materials SI move along the blade 9 to the perimeter of the plate'where they dropofi. As indicated, this strata or, layer comprises light weight particles of the material to be separated and also portions of separating media suchas sand. Obviously the flow from the plate can. bev screened whereby the separating media is removed from the material such as coal and returned back to the feed end of the trough for reintroduction into the hoppers 2 and 3.- Likewise, the return flow of separating media can be screened so that the specific gravities of the particles of media reintroduced into the hoppers 2 and 3 are the same as the original charge of medium. As shown in Figure 2, the heavy Weight particles are carried by the plate and disk until In Figures 1 and 2 charged. from thetrough'J 1 flowing laterally thereof due to the rotation of' the plate reach the perimeter of the disk over a wider area than the initial area at the base of the trough.- The light weight substances SI initially, reaching the I plate farther away from the axis thanithe heavy weight substances S2 will naturally reacl'rrthe perimeter of the plate in spaced relation to the heavyweight substances which tend to follow the surface of the disk. Thus, the'blades llwhi'eh are'adjustable can divide the stream passing over the edge of the plate in the different strataof different specific gravities. 'Here again the re-'- moved strata can be screened so that thesepa rating medium is separated from the coal on the one hand and slate or rock on the other, :and

which medium can be further screened and reintroduced into the hoppers 2 and 3. i V

Thus, it is clear thatin'both forms of the invention I have provided in combination-with a closed inclined. trough sloped at an angle greater than the natural angle of repose of-the separating medium a rotatableplate' disposed at an angle to the axis of the trough and a'-disk' above the plate having a conical surface-sloping at substantially the same angle asthe angle of slope of the trough and which trough has; a

a discharge opening facing the direction of rotation, the stream of material and the medium stratifying during its flow through-the trough and hitting plate portions having relative velocities; the plate and disk thus constituting conveying means at the lower end of the trough-which continue the flow of the stream in anarcuate path and carry the strata of the stream at different relative velocities corresponding to lithe radius of the circle of the path they respectively:

and material to be separated therein and said;

trough being at least slightly more inclined'than the natural angle of repose of. said medium so that the mass of medium and materials flows downwardly, means at the upper endof the trough for feeding the materials to be separatedand the medium to the trough, rotatable con-- veying means at the lower end of the trough rotating in such direction as to continue the flowof said stream in an arcuate path, said conveying means receiving and carrying strata of said stream at different velocities corresponding to the radius of the circle they have to follow, said:-

conveying means comprising a rotatable plate and a truncated cone-shaped member mounted above the plate having its conical surface slop-- ing in the plane of the bottom of the trough, andmeans mounting said member for movement eccentrically of the plate for pushing the strata and materials therein discharged from the trough to the perimeter of the moval.

2. In an apparatus for specific gravity ola'ssh fication of bulk substances the combination- 0f an inclined trough including top, bottom and opposite side walls and terminating inupper and lower ends, means at the upper end of the trough I plate for separate re- 61? iseparately feedings-finely granulated;

artruncated-ccneeshaped member mounted; above the plate-member and'having ltsconicallsurface:

atisnbstantially the same" angle .as 'and' sloping inrtheplaneiof the bottom i ofqtherrtrcugh; the, bottomof. said-trough terminating approximately at the upper surface of; saidi-coneshaped'memher, the sidewall. of 'said .trough'facing the directionxof rotation for said plate terminating in. spaced relationtosaid'plateto provide alateral discharge :opening' and the top and opposite side walls of'said trough projecting beyond said first mentioned side wall andterminating' immediate? lyadjacent the surface of said plate whereby difierent strata: of, substances and medium impinge upon-the. plate. at different distances :from that-center thereofgthus: upon portions having difierent relative: velocities, and the plate carrying-said strata 'laterally' of, saidi trough at differentvelociti'es; corresponding to the radius of the: circle the: difierent; weight strata follow, and thestrata being removed from the plate at different portions of itsperimeter'.

- 3;; In an" apparatus asdcfinedinand by-claim 2-,.:-in;which stationary blades project over said. plate: so: that the different strata are removed. therealongsaid.blades. being inclined at sub-' stantially the. same: anglelas the anglev of slope of said trough,

4; Inan apparatus for'separating' materials according to specific gravities,.the combination of an. inclined trough; means for feeding tothe upper endiof. said trough a mass ofa finely granulated separating medium .to. form a. lower stratum in saidtrough; means" for feedingto the. upper end, of saidltroughamass or a. finely granulated separating medium to formv an. upper stratum in said. trough; means for. feeding. to the. upper end of said; trough the materials to' be separated i'nter-- 3 mediate said lower andupper strata, the inclinaticnlof said .trou'ghlbeingf sufiicientlygreate'r than the: natural angle of repose of said masses to causersaid massesuand said materials to flow downwardly throughsaid trough; means for; dis:-

charging: said: strataand the separatedmaterials:

thereinifromthe lower end of said trough at dif-- ferentJreIatiVe. velocities, comprising a rotatable member adjacent the dischargeend of said trough and havingitwosurfacesmoving at different relativle'velocities, respectively, when said member-is:

rotated, means for discharging said strata and the separated materials therein from said trough tQ-said surfaces, respectively; and means for removing thelclischarged strata-and materials from i said surfaces;

5.. In an apparatus for separating materials-acm cording to specific. gravities,. the. combination of an. inclined trough; means for feeding to the up-" pervend of said trough a mass of a finely granulated separatingmediumto form allower stratum in said trough; means. forfeeding: to the. upper ferent relative velocities; comprising a rotating.

plate adjacent the discharge end of "said trough, means for discharging said-strata and the separated materials therein from-"said trough onto areas-of said plate atsdiiferent distances from the axis of rotation of plate; respectivelfi and means for removing the discharged strata'rand materials thereinfrom said-plate, separately.

,- I E? nan-apparatus for separating materials ac=- cording to specific gravi tie's, the combination of an inclined trough; means for feeding to theup per end of 'saidtrough' a mass of a finely granu lated separating m'edi-u-m'tdform a lower stratum in said trough," means for feedin to the 'ujpper end of said trough a-masso'f afinely granulated separating-mediumto form an upper stratum in said trough; means forfeedi'ng to the'upper'end of said trough the materiais'to-be separated in termediate said'iower and upper strata, the mclination' of saidtrou'gh being sufifi'cientlygreater' thahthenaturalangleof repose of said masses'to' cause said masses" and said materials t'o fiow downwardly through said trough; means for dis chargingsaidstrata and the separatedmaterials therein-from thelower end of saidtrough at diff erent' relative velocities including a rotating plate adjacent the discharge end of thesaid trough, a-truncated-cone-shapeddisk mo'untedon said plate; whose =surface-slopes in the plane-of: the bottom of said trough, means for discharging said strata and the separated materials therein from said-trough onto areasof-said piateat-different distances from the axis of rotation of said plate, respectively; and means for removing the miter Date I 

